A state of emergency has been declared in Houston, Texas, following the onset of tropical storm Harvey. Flash floods caused by the storm have killed at least five people and rendered thousands homeless.

According to the US National Weather Service, the situation is “unprecedented”, with the city recording a record 50 inches of rainfall. Most schools, including two airports have been flooded and are reportedly closed for the time being.

Most places in Houston have reported a loss of electricity, and people have been advised to stay indoors. These precaustions have been taken even as several interim shelters have been opened across the state to help those affected.

Meanwhile, the US Department of Transportation has deployed more than 400 people and enforced 250 highway closures across the state. Approximately 2000 people have been rescued by the state thus far with the help of both helicopters and boats.

According to the US Meteorological Department, weather conditions will continue to worsen over the coming week as Harvey is expected to move over Louisiana, Galveston and then back to Houston.

While it is still early days, some experts have estimated that the damage caused by the Harvey may dwarf the damage inflicted by Hurricane Katrina in 2005, the most expensive natural disaster in American history.

A lies abandoned after heavy damage when Hurricane Harvey hit Rockport, Texas on August 26, 2017. Hurricane Harvey slammed into the Texas coast late Friday, unleashing torrents of rain and packing powerful winds, the first major storm to hit the US mainland in 12 years. (MARK RALSTON / AFP)

ndrew White (L) helps a neighbor down a street after rescuing her from her home in his boat in the upscale River Oaks neighborhood after it was inundated with flooding from Hurricane Harvey on August 27, 2017 in Houston, Texas. (Scott Olson/Getty Images/AFP)

Water flows down Interstate 10 which has been inundated with flooding from Hurricane Harvey on August 27, 2017 in Houston, Texas. Harvey, which made landfall north of Corpus Christi late Friday evening, is expected to dump upwards to 40 inches of rain in Texas over the next couple of days. (Scott Olson/Getty Images/AFP)

People are rescued from a hotel by boat after Hurricane Harvey caused heavy flooding in Houston, Texas on August 27, 2017. Massive flooding unleashed by deadly monster storm Harvey left Houston -- the fourth-largest city in the United States -- increasingly isolated as its airports and highways shut down and residents fled homes waist-deep in water. (MARK RALSTON / AFP)